Comment Report Form for WECC-01001

Posting 3

The WECC-0100 TPL-001-WECC-CRT-3, System Performance Drafting Team (DT) thanks everyone who submitted comments on the proposed document.

Posting

This document was last posted for a 30-day public comment period fromJuly 24 through August 24, 2015.

WECC distributed the notice for the posting onJuly 23, 2015. The DT asked stakeholders to provide feedback on the proposed document through a standardized electronic template. WECC received comments from 13 respondents representing six of the eight Industry Segments, as shown in the WECC Standards Voting Sector table that follows.

Location of Comments

All comments received on the document can currently be viewed in their original format on the project page under the “Submit and Review Comments” accordion.

Changes in Response to Comment

After consideration of comments received, the DT made the following changes:

Purpose Statement

Purpose:To facilitate coordinated near-term and long-term transmission planning for the Western Interconnection, and to facilitate the exchange of the associated planning information for normal and abnormal conditions.

This document applies to all transmission planning studies conducted within the Interconnection of the Western Electricity Coordinating Council (WECC).

Facilities Section

4.1.Facilities:

4.2.1.This document applies to BulkElectric System (BES) substations buses.

4.2.2.Each of the following elements is specifically excluded from this Criterion:

4.2.2.1.Non-BES buses.

4.2.2.2.Line side series capacitor buses

4.2.2.3.Line side series reactor buses

4.2.2.4.Dedicated shunt capacitor buses

4.2.2.5.Dedicated shunt reactor buses

4.2.2.6.Metering, fictitious, or other points of interconnection modeled solely for measuring electrical quantities; and,

4.2.2.7.Other buses specifically excluded by each Planning Coordinator or Transmission Planner internal to their system.

Requirements and Measures

Requirement WR1.1 now reads (emphasis added):

1.1.Steady-state voltages at all applicable Bulk-Electric System (BES) buses shall stay within each of the following limits:

1.1.195 percent to 105 percent of nominal for P0[1] event (system normalpre-contingency powerflow);

1.1.2 90 percent to 110 percent of nominal for P1-P7[2] events (post-contingencypowerflow).

Requirement WR1.5 and 1.6 Rationale Box has been redrafted for clarity.

Requirement WR1.1.6 now includes the word “all” as a definitive (emphasis added):

1.6All oscillations that do not show positive damping within a 30-second time frame shall be deemed unacceptable.

Requirement WR2 typo has been corrected from R2 to WR2.

Requirement WR5 was redrafted for clarity (emphasis added):

WR5.Each Transmission Planner and Planning Coordinator shall use the following minimum criteria when identifying voltage stability:

Effective Date

The Effective Date has been redrafted as follows:

“The Effective Date is the later of January 1, 2016 or the Effective Date of TPL-001-4, Transmission Planning Performance System Requirements, Requirements R2-R6 and R8.”

Implementation Plan

An Implementation Plan was included in the preamble of Posting 3.

Minority Position

The DT opted not to accept Modesto’s suggestion to identify all entities containing specific tariff requirements. Including a static list of each entity would require a full examination of all entities within WECC. Further, it would require re-opening this document each time an entity changed.

Action Plan

TEXT

Pending items from the Posting 1 include:

  • Evaluation of whether to adopt, modify, or delete WR1.4 Table W-1.To do so is within the scope of the Standards Authorization Request but is not mandated. (Xcel)
  • Evaluation of whether to retain the PRC-024-1 curve in the document.(Idaho Power)
  • White paper
  • The drafting team committed to pursuing a white paper to address simulations needed to justify and refine the proposed criteria.Drafting efforts on the paper have begun in consultation with the Modeling Validation Work Group. (BPA, Xcel)

Contacts and Appeals

If you feel your comment has been omitted or overlooked, please contact the Manager, WECC Standards Processes, W. Shannon Black, at . In addition, there is a WECC Reliability Standards Appeals Process.

The WECC Standards Voting Sectors are:

1 — Transmission Sector

2 — Generation Sector

3 — Marketers and Brokers Sector

4 — Distribution Sector

5 — System Coordination Sector

6 — End Use Representative Sector

7 — State and Provincial Representatives Sector

8 — Other Non-Registered WECC Members and Participating Stakeholders Sector

Commenter / Organization / WECC Standards Voting Sectors
1 / 2 / 3 / 4 / 5 / 6 / 7 / 8
1 / Spencer Tacke / Modesto Irrigation District / X / X / X / X / X
2 / James Hirning / Western Area Power Administration / X / X / X / X / X
3 / Gordon Comegys / G2 Power Consulting / X[3]
4 / Ryan Hubbard / Tri-State Generation and Transmission, Inc. / X / X / X / X / X
5 / Eleanor Ewry / Puget Sound Energy / X / X / X / X / X
6 / Venkataramakrishnan Vinnakota / BC Hydro / X / X / X / X
7 / Hamody Hindi / MVWG / X[4]
8 / Gary Trent / Tucson Electric / X / X / X
9 / Jeff Watkins / NV Energy / X[5]
10 / Jeremy Brownrigg / Platt River / X / X / X / X / X
11 / Joshua Anderson / Salt River Project / X / x / X / X / X
12 / Stephanie Lu / Seattle City Light / X / X / X / X / X
13 / Anupama Pandey / Pacific Gas and Electric / X / X

Index to Questions, Comments, and Responses

Question

  1. The drafting team welcomes comments on all aspects of the document.

1.The drafting team invites comments on all aspects of the document.

Summary Consideration: / See summary in the preamble of this document.
Commenter / Yes / No / Comment
Modesto /
  1. Recommendation that the Rationale document, which includes the waveform diagrams, should be part of the TPL-001-WECC-CRT-3 Criterion document in total.
  2. Under the Rational for Requirement WR1.2, please indicate who the "certain entities are" that are bound by state tariffs that establish the eight percent voltage deviation. Also, in regards to the statement that the eight percent target is established based on sound engineering judgment, making an engineering judgment still requires a reference point. Where is that reference and supporting data for the eight percent value?
  3. Recommend revising Section 1.3's phrase "within 10 seconds" to "within 20 seconds". This recommendation is based on observation of demonstrated actual system FIDVR event data, indicating that typical voltage recovery times to within 80% of the pre-event voltage value, are larger than 10 seconds, and are typically 15 to 20 seconds.
  4. Recommend revising Section 1.6 to add the word "All" before the word "Oscillations".

Issue 1:Move Rationale to the Main Body
Pending
Issue 2:Under the Rational for Requirement WR1.2, designate all entities
The DT opted not to accept Modesto’s suggestion. Including a static list of each entity would require a full examination of all entities within WECC. Further, it would require re-opening this document each time an entity changed.
Issue 3:Supporting data for 8% reference point
Pending
Issue 4: Revise Section 1.3's phrase "within 10 seconds" to "within 20 seconds"
Pending
Issue 5:Section 1.6, add “All” before “Oscillations”
The word was added.
Western Area Power Administration / ​​​​​​1. WR1.1.2. The upper limit has changed since posting 2.
In order for this to move forward it needs to return to 110 percent of nominal.
ANSI/NEMA C84.1 shows the maximum system and utilization voltages as 1.05. The statement on system voltage in C84.1 Section 5.1.1 does not preclude voltages outside this range, but state "The occurrence of service voltages outside these limits should be infrequent." Additionally, in the Scope of the document, Section 1.1, the standard states "In defining maximum system voltage, voltage transients and temporary over voltages caused by system conditions such as faults, load rejection, and the like are excluded." And, Section 2.2.3 states that the maximum system voltage is "the highest system voltage for which equipment and other components are designed for satisfactory continuous operation without de-rating of any kind." This does not preclude their use at higher voltages with de-rating. Equipment manufacturers tell us that they state their high-end voltage level for operation is deemed as 1.05 p.u., but the equipment will not malfunction at voltages outside this. 1.10 p.u. has been the threshold used since the 1970's as the high-bookend voltage to hold to for any studied contingency. Therefore, this limit is historically proven, and to propose a change here would unravel years of planning studies.
2. WR1.3, WR1.4, and WR1.5 seem like adequate efforts to measure system performance, but in practice, at times, they may be unclear whether they are measuring system performance or system modeling. For example, suppose there is one pumping load bus in a neighboring system that slightly dips below these criteria in a transient study after a contingency. There is not a specific relay modeled to trip the load, although the planner believes some sort of protection could trip it. Even if the load hangs one, it does not affect other bus voltages in the system. Has the performance criterion been violated?
Requiring a strict adherence to these stated values may be difficult for some contingencies, especially P5 through P7 events, which allow for Non-Consequential load loss.
Additionally, entities are currently completing TPL studies according to the TPL-001-4 to be compliant by January 1, 2016. Likely, entities have already adopted a criterion of their own or are using the prior "finger" diagram.
These criteria could be revised to allow for more latitude if they are violated. For example, perhaps these criteria could be labeled as a "proxy" for distribution level relay operation. In this manner, the planner must assume loads on these buses tripped, and the planner must also show the disturbance is contained (even if the load does not trip).
3. In WR1.6, there should be some additional language to clarify what will probably be confusion about whether the "30 second time frame" is simply any 30 second window, or whether it is specifically the 30 second window that begins after fault clearing (or after a no fault P2.1 event) and ends exactly 30 seconds later.
4. WR2 and WR3 allow any entity to have different requirements than those given in WR1. The effectively makes WR1 NOT a requirement.
Furthermore, allowing entities to define more stringent or less stringent voltage limits on certain parts of their system for the steady-state simulation will be nearly impossible to implement unless WECC [begins] sic asking for bus voltage limit criteria to be input into base cases (similar to the MVA ratings). In the transient simulations, there may not be any good way for entities to monitor varying requirements that have been defined on each bus in other systems.
Additionally, there is no clear mechanism to enforce whether entities are abiding by less restrictive or more restrictive limits that have been defined. What happens if an entity defines a less restrictive limit, but then later desires to go back to the limit stated in WR1?
WR2 and WR3, therefore, do not provide value to this document if it is to remain a criterion.
5. In WR4, the first bullet should be clarified to say "results in steady-state facility loading." The second bullet may be too stringent in identifying potential cascading as "any" applicable BES bus voltage outside the stated transient limit. As explained above, strict adherence to these stated values may be difficult for some contingencies, especially P5 though P7 events, which allow for some Non-Consequential load loss.
6. Western would prefer that this re-write be categorized as a Guideline vs. Criteria document. WR1 includes what can be interpreted as criteria - the voltage levels for N-0 and N-1; however, WR2 and Wr3 allow folks to have differing "criteria". So it seems, this basically undoes WR1 and the document no longer reads as a Criteria. Categorizing as a Guideline can be accomplished by doing away with WR1 through WR4 as proposed and re-write WR6 to say that each TP and PC shall provide its TPL-001-4 R5 voltage criteria upon request. Put WR1 and WR4 as a Guideline. Then WR5 and WR6 become WR1 and WR2 respectively.
7. The introduction says, "This document applies to all transmission planning studies conducted at the Western Interconnection level." WR5 requires the Transmission Planner and Planning Coordinator to identify voltage stability. Does this mean that the Criterion requires WECC entities to perform a post-transient voltage stability analysis for annual TPL assessments, even though NERC TPL-001-4 only requires steady-state, transient, and short-circuit analysis? Perhaps more clarity could be added here to answer that question.
8. As currently written, the proposed criterion doesn't state anything about allowable effects on your neighbors, which is what some folks seemed concerned about. The current TPL Criterion Table speaks specifically about allowable effects on your neighbor. This issue needs to be addressed.
9. There seem to be some minor formatting errors, and the words "Transmission Planner" and "Planning Coordinator" should be spelled out throughout the document.
Issue 1:WR1.1.2. Return upper limit to 110% (as in Posting 2)
The DT accepted the suggestion. WR1.1 now reads:
1.2.Steady-state voltages at all applicable Bulk-Electric System (BES) buses shall stay within each of the following limits:
1.1.195 percent to 105 percent of nominal for P0[6] event (system normal pre-contingency powerflow);
1.1.2 90 percent to 110 percent of nominal for P1-P7[7] events (post-contingency powerflow).
Issue 2:WR1.3, WR1.4, and WR1.5 revise to allow more latitude / proxy for distribution
PENDING
Issue 3:WR1.6, clarify “30 second time frame" – a general or specific window
PENDING
Issue 4:WR2 and WR3 cancel out WR1 – WR1 is void
The DT does not concur that WR2 and WR3 cancel out WR1. To clarify the interaction between the three requirements, the following information has been added to the Rationale block.
WR1 is designed to state the base criteria at which the study must be conducted – unless otherwise specified. WR1 is the default whereas WR2 and WR3 allow for an exception to the default.
Neither WR2 nor WR3 changes the WR1 default; rather, both WRs create an allowable deviation form the default. WR2 allows for a more stringent approach without changing the WR1 default. A more stringent approach may be used in accordance with WR2 so long as all the affected parties agree. Similarly, WR3 allows deviation from the default with the additional protection that when used, other Transmission Planners and Planning Coordinators are allowed to use the same criteria on that part of the system for the same category of planning events (e.g., P1 and P2).
Issue 5:Impossible to implement without WECC intervention
Pending
Issue 6:What happens if an entity defines a less restrictive limit, but then later desires to go back to the limit stated in WR1?
Pending
Issue 7:WR4, bullet 1 clarify to say “results in steady-state facility loading."
Pending
Issue 8:Guideline or Criteria
The DT agreed to request that the Planning Coordinating Committee (PCC) place an approval item on its October 2015 agenda to seek industry consensus on which type of document this project should represent: a WECC Criterion or a WECC Guideline. The DT consensus remains that the document should be WECC Criterion.
The DT is seeking final disposition on the issue and is in hopes of solidifying consensus by the voting constituency. Although an earlier PCC straw poll (July 2013) had concluded that a WECC Criterion best suited the project, subsequent understanding of document categorization and the current trajectory of the project may have swayed that advisory position.
Issue 9:WR5 / Does this mean that the CRT requires entities perform a post-transient voltage stability analysis for annual TPL assessments, even though NERC TPL-001-4 only requires steady-state, transient, and short-circuit analysis?
To clarify the language, the DT redrafted WR5 as follows:
WR5.Each Transmission Planner and Planning Coordinator shall use the following minimum criteria when identifying voltage stability: (emphasis added)
Issue 10:Silent on allowable effects on your neighbors
The DT disagrees with WAPA’s interpretation of the interaction between WR1, WR2, and WR3. Please refer to the language added to the WR1 Rationale block. WR2 protects ones neighbors in that a more stringent criteria cannot be used without communication and collaboration between the affected parties. WR3 protects ones neighbors in that one’s neighbors are allowed to use the less stringent criteria to prevent any adverse impact.
Issue 11: Formatting
The document will be screened for technical writing at or near the termination of the drafting process.
G2 Power / The rationale for WR1.2 states "only automatic post-contingency actions including capacity or reactor switching are considered when calculating voltage deviation". Please provide a maximum time for automatic actions. For example, automatic voltage controls at some generators slowly restore high side voltage at the GSU to a voltage schedule 10-20 minutes after the initial voltage deviation. Should this action be included in the calculation?
Issue 1: Rationale WR1.2 / Provide maximum time for automatic actions
Clarification of the WR was added in the Rationale box.
The following sentence has been elaborated.
“By default, only automatic post-contingency actions occurring in the studied timeframe, including capacitor or reactor switching, are considered when calculating voltage deviation.” (emphasis added)
This rationale recognizes that differing time windows may be studied at different times.
Tri-State / ​Here are the comments gathered from people at Tri-State.​
  • There are three diagrams, the first showing FIDVR criteria, the second showing normal voltage recovery criteria, but I can't tell what the third one is or why it is there.
  • The second diagram should have two time spans shown, one for length of voltage dip less than 80% of pre-contingent voltage, and the other for length of dip less than 70% of the same.
  • Is there a voltage dip minimum value that should not be exceeded for any length of time?
  • Does the voltage dip criteria apply to the FIDVR response plots as well? I would think so.
  • The initial voltage does not line up on Figure 2.
  • After reading the Technical Discussion, I disagree with the conclusions and resulting recommendations. Given that the P0-P7 events have different fault types, and given that the IEEE Standard 1668 has recommended criteria for different fault types, I disagree with the blanket approach to the recommended criteria of "not below 70% for more than 30 cycles for all P1-P7events." This is a fairly major departure from the criteria used currently, and it is not appropriate for all events in the P1-P7 range. In other words, the events that are specified as 3-phase faults in the P1-P7 event definitions should adhere to the more stringent criteria recommended in IEEE 1668 of "not below 70% for more than 6 cycles," which also lines up better with the practices in place currently.